[Amino acid composition of proteins in sun and shade leaves of the copper beech (Fagus sylvatica L. cv. Atropunicea)].

The amino acid contents of sun and shade leaves of the copper beech are significantly different. On the basis of dry matter, the concentration of the majority of amino acids is higher in shade leaves. Only the concentrations of proline, valine, histidine and arginine are about 30% lower compared with those of the other amino acids. Calculated on the basis of crude protein, the concentrations of lysine, histidine, arginine, valine, isoleucine and proline are considerably lower in shade leaves than in sun leaves. On the other hand, shade leaves contain more tyrosine, phenylalanine, and methionine.A hypothesis interpreting the different morphogenesis of sun and shade leaves in connection with the high proline content of sun leaves is discussed.